Michael Dawson has already lost 1000 acres and now another 1000 acres is under threat.

Rosemary Shepherd has had 1600 acres of crops flooded and Charles Brett is watching the water enter his property.

Under the local water sharing plan in the lower Gwydir there are several types of water that can go to the wetlands including what's known at the Three Tributaries flow (or 3T).

3T water is natural flow from the three main upstream tributaries, the Horton, the Myall and the Halls Creek. It goes down the Gingham watercourse and Lower Gwydir River.

Under the Water Act the first 500 ML is protected from diversion.

The current water sharing plan was established in 2004 and has not been tested in the kind of saturated environment being experienced at the moment.

With the catchment saturated, what would normally be a low flow of 500 ML is causing serious problems for farmers in the lower Gwydir.

The farmers argue the local water sharing plan has not been tested in these type of wet condition being experienced and since the Federal Government purchased a property called 'Old Dromana'.

The Commonwealth spent $10 million buying both water rights and the property in February 2010.

It contains 600 hectares, or around 74 per cent, of the internationally recognised wetlands in the area, and is a key breeding site for waterbirds.

The farmers want urgent action to stop the flows or divert the water down the Mehi.

The Water Surface Manager from the NSW Office of Water, Paul Simpson said there is some discretion allowed within the system.

"If in the opinion of the minister, diverting the flows somewhere else other than the Gwydir wetlands will be beneficial to the environment, that can happen, that decision would have to be made after receiving advice from the advisory committee that has been set up under the water sharing plan."

"It is physically possible to divert the water, but it depends on what other flows are already being diverted down the Mehi, but is obviously not what the plan is intending."

The NSW Farmers Association President, Fiona Simson said it is looking into the situation.

She said it highlights the current debate about the Murray Darling Basin Plan.

"Unfortunately what we are seeing, particularly with the progression of the MDBP and the provision for environmental watering, we are seeing that these plans are being made without any proper understanding at all about how they are going to interact with what is currently happening on the land, and how they will work with other provisions that are in place."

The NSW Water Commissioner, David Harris said the size of this flow event means that it is not possible to avoid significant volumes passing into the Gwydir wetlands.

He said the department will meet with local farmers in August and hold a workshop on the issue.